Exhaust Manifold Gasket – Fits MerCruiser 140 HP 3.0L 4-Cyl Engines (Replaces 27-53354, 18-2912)

Exhaust Manifold Gasket – Fits MerCruiser 140 HP 3.0L 4-Cyl Engines

This exhaust manifold gasket is designed for MerCruiser 140 HP (3.0L/181 CID) 4-cylinder, GM-based Stern Drive engines from 1968 to 1982. It serves as a direct-fit replacement, ensuring a reliable seal for wet joint exhaust systems.

This component is a direct replacement for OEM and aftermarket part numbers, including Mercury/MerCruiser 27-53354, Sierra 18-2912, GLM 31570, and Mallory 9-61417.

• Installation Type: Designed for a wet joint connection between the exhaust manifold and the cylinder head.
• Fuel Compatibility: Gasoline
• Included Components: Contains one exhaust manifold gasket.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Exhaust Manifold Gasket (27-53354)

Installation Guide

1. Safety First: Disconnect the battery terminals and ensure the engine is completely cool.
2. Drain Coolant: Drain the engine's cooling system to prevent spills when the manifold is removed.
3. Remove Components: Disconnect any hoses, wires, or brackets attached to the exhaust manifold.
4. Unbolt Manifold: Loosen and remove the bolts securing the exhaust manifold to the cylinder head. Carefully detach the manifold.
5. Remove Old Gasket: Take off the old gasket and dispose of it. Be prepared for some adhesion.
6. Clean Surfaces: Thoroughly clean the mating surfaces on both the cylinder head and the exhaust manifold. All old gasket material and residue must be removed for a proper seal.
7. Position New Gasket: Place the new gasket correctly over the dowels or bolt holes on the cylinder head.
8. Reinstall Manifold: Carefully place the exhaust manifold back into position and hand-tighten the bolts.
9. Torque Bolts: Tighten the manifold bolts to the manufacturer's recommended torque specifications and sequence.
10. Reconnect Components: Reattach all hoses, wires, and brackets that were previously removed.
11. Refill and Test: Refill the cooling system. Reconnect the battery. Start the engine and carefully check for any coolant or exhaust leaks around the gasket area.

Troubleshooting & FAQ

How do I confirm this fits my engine?
Verify your engine model and year are listed in the "Compatible Engine Models" table. It is critical to also cross-reference your existing part number with those in the "Part Number Cross-Reference" list to ensure an exact match before ordering.

What are the signs of a failing exhaust manifold gasket?
Common symptoms include water or steam leaking from the manifold-head joint, engine overheating, poor engine performance, or finding water in the engine cylinders. A visible crack or degradation of the old gasket material upon inspection is also a clear indicator.

What is the difference between a wet joint and dry joint exhaust?
This is a wet joint gasket, meaning it is designed for systems where engine coolant passes through channels between the manifold and cylinder head. Dry joint systems do not have these coolant passages. Ensure you have correctly identified your engine's exhaust configuration before installation.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.